Breathable residual-limb socket system

ABSTRACT

Breathable residual-limb system that admits air and allows sweat to evaporate from the surface of the residual limb. In an embodiment, the system comprises a liner sock to be worn on the residual limb, and comprising air-permeable textile forming a substantially cylindrical portion that is closed on a distal end and open on a proximal end and comprising an internal surface and an external surface. The liner sock further comprises a friction-interface material that covers only a portion of the internal surface of the air-permeable textile, such that, when worn on the residual limb, the friction-interface material contacts a surface of the residual limb, and an uncovered portion of the air-permeable textile which the friction-interface material does not cover allows air to pass between an external environment of the liner sock and the surface of the residual limb.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent App. No.62/530,762, filed on Jul. 10, 2017—the entirety of which is herebyincorporated herein by reference.

GOVERNMENT LICENSE RIGHTS

This invention was made with government support under Contract No.W81XWH-14-2-0197, awarded by the Department of Defense. The governmentmay have certain rights in the invention.

BACKGROUND Field of the Invention

The embodiments described herein are generally directed to a residuallimb socket system, and, more particularly, to a breathableresidual-limb socket system that admits air and allows sweat toevaporate from the surface of the residual limb.

Description of the Related Art

Conventional residual-limb socket systems utilize a liner, which ispulled over the residual limb, in conjunction with a socket, which ispulled over the liner. However, these conventional prostheses often usematerials that have thermally insulating properties. For example,conventional liners are made of thick rubber, foam, or leather. Thiscreates a microclimate in which heat, trapped inside the socket, canmake the residual limb hot, sweaty, and uncomfortable. These hot, moistconditions within the prostheses can exacerbate skin problems on theresidual limb, as well as reduce mobility and function of the residuallimb.

Some liners, such as the Endolite Silcare Breathe™ and Uniprox SoftSkinAir™, have micro-pores to improve breathability. However, as confirmedby testing, even with these micro-pores in the liner, the residual limbis not able to receive the amount of air necessary for evaporativecooling.

Thus, what is needed is a breathable residual-limb socket system that issufficiently air-permeable so as to allow evaporative cooling on thesurface of the residual limb.

SUMMARY

Accordingly, a breathable residual-limb socket system is disclosed. Inan embodiment, the system comprises a liner sock to be worn on theresidual limb, the liner sock comprising: air-permeable textile forminga substantially cylindrical portion that is closed on a distal end andopen on a proximal end and comprising an internal surface and anexternal surface; and a friction-interface material that covers only aportion of the internal surface of the air-permeable textile, such that,when worn on the residual limb, the friction-interface material contactsa surface of the residual limb, and an uncovered portion of theair-permeable textile which the friction-interface material does notcover allows air to pass between an external environment of the linersock and the surface of the residual limb.

In an embodiment, the air-permeable textile comprises: a first sectioncomprising unidirectional-stretch textile; and at least one secondsection comprising bidirectional-stretch textile. The first section maybe fixed to the at least one second section by at least one seam, andthe friction-interface material may cover the seam on the internalsurface of the air-permeable textile. The air-permeable textile maycomprise two second sections comprising bidirectional-stretch textile.The friction-interface material may cover an entire internal surface ofthe first section comprising unidirectional-stretch textile, but notcover an entire internal surface of the at least one section comprisingbidirectional-stretch textile.

In an embodiment, the friction-interface material comprises a pluralityof longitudinal strips that extend in a longitudinal direction of theliner sock and that are spaced apart from each adjacent one of theplurality of longitudinal strips, around a circumference of the linersock, by the uncovered portion of the air-permeable textile. Thefriction-interface material may comprise a strip that extends around acircumference of the liner sock at a proximal end of the liner sock. Thefriction-interface material may comprise a plurality of circumferentialstrips that extend around a circumference of the liner sock and that arespaced apart from each adjacent one of the plurality of circumferentialstrips, in a longitudinal direction of the liner sock, by the uncoveredportion of the air-permeable textile. In an embodiment, thefriction-interface material comprises a plurality of dots. Thefriction-interface material may comprise a distal cup at a distal end ofthe liner sock. The friction-interface material may comprise siliconegel.

In an embodiment, the liner sock further comprises a distal cap on anexternal surface of the closed distal end of the liner sock. The distalcap may comprise a countersunk threaded hole configured to receive ascrew pin.

In an embodiment, the system further comprises a socket to be worn,either directly or indirectly, over the liner sock, the socketcomprising: a perforated inner layer; and an outer frame comprising oneor more fenestrations, through which the perforated inner layer isexposed to an external environment of the socket. The perforated innerlayer may comprise a plurality of holes having a diameter of 5millimeters or less. The outer frame may comprise an anteriorfenestration and at least one posterior fenestration. The outer framemay comprise at least two posterior fenestrations. The perforated innerlayer may comprise fabric. The outer frame may comprise carbon fiber.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of the present invention, both as to its structure andoperation, may be gleaned in part by study of the accompanying drawings,in which like reference numerals refer to like parts, and in which:

FIGS. 1A-1C illustrate exterior perspective views of a liner sock,according to an embodiment;

FIGS. 2A-2C illustrate exterior plan views of a liner sock, according toan embodiment;

FIGS. 3A and 3B illustrate interior plan views of a liner sock,according to a first embodiment;

FIGS. 4A and 4B illustrate interior plan views of a liner sock,according to a second embodiment;

FIGS. 5A and 5B illustrate interior plan views of a liner sock,according to a third embodiment;

FIGS. 6A and 6B illustrate interior plan views of a liner sock,according to a fourth embodiment;

FIGS. 7A and 7B illustrate interior plan views of a liner sock,according to a fifth embodiment;

FIG. 8A illustrates a layer of a socket, according to an embodiment;

FIGS. 8B-8F illustrate various exterior views of a socket, according toa first embodiment;

FIGS. 9A and 9B illustrate exterior views of a socket, according to asecond embodiment; and

FIGS. 10A-10C illustrate usage of a liner sock and socket, according toan embodiment.

DETAILED DESCRIPTION

In an embodiment, a breathable residual-limb socket system is disclosed.After reading this description, it will become apparent to one skilledin the art how to implement the invention in various alternativeembodiments and alternative applications. However, although variousembodiments of the present invention will be described herein, it isunderstood that these embodiments are presented by way of example andillustration only, and not limitation. As such, this detaileddescription of various embodiments should not be construed to limit thescope or breadth of the present invention as set forth in the appendedclaims.

1. System

In an embodiment, the breathable residual-limb socket system comprisesone or both of a liner sock and a socket.

1.1. Liner Sock

FIG. 1A illustrates a perspective view, from a distal end to a proximalend, of the front of the exterior of a liner sock 100, while FIG. 1Billustrates a side of the exterior of liner sock 100 (e.g., the linersock 100 in FIG. 1A, rotated 90° to the left), according to anembodiment. Liner sock 100 may be formed from at least one section 110of unidirectional-stretch textile and at least one section 120 ofbidirectional-stretch textile. The unidirectional-stretch textile ofsection(s) 110 is manufactured to have elasticity primarily in a singledirection (e.g., in the longitudinal direction of liner sock 100),whereas the bidirectional-stretch textile of section(s) 120 ismanufactured to have elasticity primarily in two directions (e.g., inthe longitudinal and lateral directions of liner sock 100). Theunidirectional-stretch textile and/or the bidirectional-stretch textileshould be air-permeable and/or breathable, so as to allow evaporativecooling through the textile.

In the illustrated embodiment, liner sock 100 comprises a single section110 of unidirectional-stretch textile and two sections 120A and 120B ofbidirectional-stretch textile. As shown sections 120A and 120B ofbidirectional-stretch textile are each generally rectangular with acurved distal end. Each section 120A and 120B of bidirectional-stretchtextile is joined to section 110 of unidirectional-stretch textile by aU-shaped seam 130A and 130B, respectively. In addition, opposing edgesof section 110 of unidirectional-stretch textile may be joined to eachother by seam 130C, to form a substantially cylindrical or partiallycylindrical liner sock 100. Bidirectional-stretch sections 120A and 120Bmay be on opposite sides of the substantially cylindrical portion ofliner sock 100, such that, around a circumference of liner sock 100,bidirectional-stretch sections 120A and 120B are spaced apart from eachother on both sides by interposed portions of unidirectional-stretchsection 110.

In an embodiment, the distal end of liner sock 100 comprises a distalcap 140 and a threaded countersunk hole 142 for receiving a screw pin146. Distal cap 140 is affixed to the distal end ofunidirectional-stretch section 100 and/or an internal distal cup (e.g.,distal cup 144, illustrated in other figures), with a distal portion ofunidirectional-stretch section 110 sandwiched between distal cap 140 andthe distal cup, to thereby close the distal end of liner sock 100.Distal cap may comprise or consist of polyurethane rubber or a similarmaterial, and may be affixed to liner sock 100 and/or the distal cupwithin liner sock 100 via stitching, adhesives, and/or the like.Countersunk hole 142 is configured to receive a standard, threaded screwpin 146, which is commonly used for the suspension of prosthetic limbs.Of course, the proximal end of liner sock 100 remains open or openableto receive the residual limb of the user.

FIG. 1C illustrates the front of liner sock 100, with the proximal endof liner sock 100 partially rolled down to show an interior portion ofliner sock 100, according to an embodiment. As shown, the internalsurface of liner sock 100 may comprise strips 150, 152, and/or 154. Eachstrip 150, 152, and/or 154 may comprise or consist of silicone gel or asimilar friction-interface material.

In an embodiment, a plurality of spaced longitudinal strips 150 extendlongitudinally (i.e., vertically when liner sock is upright) down theinternal surface of liner sock 100. A circumferential strip 152 may alsobe provided around the entire circumference of liner sock 100 at or nearthe proximal end of liner sock 100. In addition, a plurality of seamstrips 154 may cover the internal surface of seams 130, to prevent linersock 100 from slipping, as well as to prevent seams 130 from irritatingthe skin of the residual limb. It should be understood that the internalsurfaces of seams 130A, 130B, and 130C may each be covered by a seamstrip 154, and that the respective seam strip 154 may follow thecurvature of seams 130A and 130B.

Strips 150, 152, and/or 154 may be sized and spaced to provide acomfortable friction fit, while allowing a significant portion of theinternal surface of liner sock 100 (e.g., 50% or more of the internalsurface) to remain uncovered. In addition, strips 150, 152, and/or 154may be positioned over targeted anatomical regions to provide cushioningto sensitive anatomical regions (e.g., the distal tibia, tibialtubercle, tibial crest, tibial condyles, fibular head, etc.) and/orsuspension loading to tolerant anatomical regions (e.g., patellartendon, medial tibial flare, fibular shaft, popliteal fossa,gastrocnemius, etc.). The friction fit, provided by strips 150, 152,and/or 154, prevents liner sock 100 from slipping off of the residuallimb during use of a suspended prosthesis, while the uncovered portionsof the internal surface of liner sock 100 (i.e., in conjunction with theuncovered external surface of liner sock 100) allow air to permeate thetextile of liner sock 100. This air-permeability of liner sock 100enables evaporative cooling on the skin of the residual limb withinliner sock 100.

FIG. 2A-2C illustrate plan views of liner sock 100, according to anembodiment. Specifically, FIG. 2A illustrates a front view of liner sock100, FIG. 2B illustrates a back view of liner sock 100, and FIG. 2Cillustrates a side view of liner sock 100. It should be understood that,with respect to liner sock 100, the terms “front,” “side,” and back” aresimply used for the convenience of relating the illustrations to eachother, and that liner sock 100 does not need to be oriented on theresidual limb in any particular fashion (e.g., the front of liner sock100 may be aligned to the posterior of the residual limb, etc.).However, to obtain the benefit of sections 120A and 120B ofbidirectional-stretch textile, one of these sections 120A and 120Bshould be oriented on the anterior of the residual limb (e.g., such thatit passes over the front of the knee), while the other one of thesesections should be oriented on the posterior of the residual limb (e.g.,such that it passes over the back of the knee).

FIGS. 3A and 3B illustrate front and side views of an internal surfaceof liner sock 100, according to a first embodiment. In other words,these views illustrate liner sock 100 when flipped inside-out. As shown,the internal surface of liner sock 100 comprises strips 150, 152, and154, which may comprise or consist of silicone gel or a similarfriction-interface material, as is commonly used for cushioningresidual-limb liners and is well known in the art. Longitudinal strips150 comprise N strips extending longitudinally across a portion or anentirety of the longitudinal length of the inner surface of liner sock100. N may be any number greater than or equal to one and preferablygreater than one. However, as discussed elsewhere herein, longitudinalstrips 150 should be numbered and spaced so as to leave uncoveredtextile between adjacent pairs of longitudinal strips 150. For example,each longitudinal strip 150 may be approximately half-an-inch in widthand be spaced from each adjacent longitudinal strip 150, along thecircumference of liner sock 100, by approximately half-an-inch or more.

While longitudinal strips 150 are shown as stopping at seams 130A and130B and not extending across sections 120A and 120B ofbidirectional-stretch textile, in alternative embodiments, strips 150may extend longitudinally across sections 120A and 120B (e.g., asdemonstrated in FIG. 1C). Circumferential strip 152 is a continuousstrip along the entire circumference of a proximal end of the internalsurface of liner sock 100. Strips 154 cover and follow the innersurfaces of seams 130, to prevent or reduce contact between seams 130and the skin of the user's residual limb, thereby preventing or reducingskin irritation.

In an embodiment, the internal surface of liner sock 100 comprises adistal cup 144. Distal cup 144 may comprise silicone gel or a similarfriction-interface material, and may comprise the same material or adifferent material than strips 150, 152, and/or 154. In an embodiment,distal cup 144 comprises the same material as strips 150, 152, and/or154, but has greater thickness. Distal cup 144 is configured tocomfortably receive the distal end of the user's residual limb.Preferably, distal cup 144 should have a low durometric measure to aidin comfort at the distal end of the residual limb.

FIGS. 4A and 4B illustrate front and side views of an internal surfaceof liner sock 100, according to an alternative, second embodiment. Inthis second embodiment, longitudinal strips 150 and seams strips 154 maybe the same as described above. However, in this second embodiment theinternal surface of liner sock 100 comprises a plurality ofcircumferential strips 152, with each circumferential strip 152extending along the entire circumference of liner sock 100. The numberof circumferential strips 152 may comprise any number greater than one.However, as discussed elsewhere herein, circumferential strips 152should be numbered and spaced so as to leave uncovered textile betweenadjacent pairs of circumferential strips 152. For example, eachcircumferential strip 152 may be approximately half-an-inch in width andbe spaced from each adjacent circumferential strip 152, along thelongitudinal axis of liner sock 100, by approximately half-an-inch ormore.

Circumferential strips 152 may be spaced substantially equidistantlyalong the longitudinal axis of liner sock 100. As shown, circumferentialstrips 152 extend across sections 120A and 120B of bidirectional-stretchtextile. However, in alternative embodiments, at least some ofcircumferential strips 152 may extend circumferentially across section110 of unidirectional-stretch textile, but stop at seams 130A and 130Bso as not to extend circumferentially across sections 120A and 120B ofbidirectional-stretch textile.

FIGS. 5A and 5B illustrate front and side views of an internal surfaceof liner sock 100, according to an alternative, third embodiment. Inthis third embodiment, seam strips 154 may be the same as describedabove, and the internal surface of liner sock 100 may comprise the sameplurality of circumferential strips 152 described in the secondembodiment illustrated in FIGS. 4A and 4B. However, in the thirdembodiment, the internal surface of liner sock 100 does not comprise anylongitudinal strips 150.

Advantageously, in embodiments which utilize a plurality of spacedcircumferential strips 152 (e.g., the second embodiment illustrated inFIGS. 4A and 4B, and the third embodiment illustrated in FIGS. 5A and5B), liner sock 100 can be cut to size and still have a proximalcircumferential strip 152. Specifically, to shorten liner sock 100 tomore appropriately match the length of the residual limb, a user can cutliner sock 100 laterally. For example, if the user cuts liner sock 100laterally between circumferential strips 152C and 152D, circumferentialstrips 152A, 152B, and 152C will be discarded with the separated portionof liner sock 100, and circumferential strip 152D will act as the newproximal circumferential strip to comfortably friction-fit the proximaledge of liner sock 100 to the residual limb.

FIGS. 6A and 6B illustrate front and side views of an internal surfaceof liner sock 100, according to an alternative, fourth embodiment. Inthis fourth embodiment, the internal surface of liner sock 100 comprisesdots 156. Like strips 150, 152, and/or 154, dots 156 may comprise orconsist of silicone gel or a similar friction-interface material, andprovide the same comfort, friction fit as strips 150, 152, and/or 154.The internal surface of liner sock 100 may still comprisecircumferential strip 152 along the proximal, internal circumference ofliner sock 100, and/or may still comprise seam strips 154 following theinternal surfaces of seams 130. Alternatively, the internal surface ofliner sock 100 may comprise only dots 156, i.e., without any of strips150, 152, and 154.

FIGS. 7A and 7B illustrate front and side views of an internal surfaceof liner sock 100, according to an alternative, fifth embodiment. Inthis fifth embodiment, the internal surface of section 110 ofunidirectional-stretch textile of liner sock 100 is entirely covered bymaterial 158, whereas the internal surfaces of sections 120A and 120B ofbidirectional-stretch textile are not covered by any material (or onlypartially covered by material 158 within a vicinity of seams 130).Notably, the internal surfaces of seams 130 may be covered by material158. Like strips 150, 152, and/or 154, and/or dots 156, material 158 maycomprise or consist of silicone gel or a similar friction-interfacematerial, and provide the same comfort, friction fit as strips 150, 152,and/or 154, and/or dots 156.

1.2. Socket

FIGS. 8A-8F illustrates a socket 200, according to a first embodiment.In the illustrated embodiment, socket 200 comprises a perforated innerlayer 210 and an outer frame 220. Socket 200 may be worn over a stumpsock 300, which is worn over liner sock 100. Stump sock 300 can be usedto provide volume management. Specifically, the volume of the residuallimb may change throughout the course of a day. Thus, stump socks 300 ofdiffering thicknesses (i.e., different ply) may be used, throughout theday, to fill the varying amounts of space between liner sock 100 andsocket 200, caused by the changes in limb volume. Stump sock 300 andsocket 200 both comprise holes at their distal ends to allow the passageof a pin screw (e.g., pin screw 146 in FIGS. 10A-10C), when the pinscrew is threaded into countersunk hole 142 of liner sock 100.

As illustrated in FIG. 8A, perforated inner layer 210 is anair-permeable layer that comprises a plurality of perforations or holes212, through which air may pass. In an embodiment, each hole may besmall (e.g., 5 millimeters or less in diameter) to avoid excessivetissue strain or other skin problems on the residual limb. Perforatedinner layer 210 may be made from polypropylene, polyethylene, nylon, orother thermo-formable plastic, or a copolymer of such plastics.

As illustrated in FIG. 8B, outer frame 220 is attached over perforatedinner layer 210. Outer frame 220 comprises one or more fenestrations orwindows, which expose one or more portions of perforated inner layer 210to the external environment. In the first embodiment, illustrated inFIGS. 8A-8F, outer frame 220 comprises three such fenestrations. Outerframe 220 may comprise or consist of carbon fiber for lightweightdurability.

In an embodiment, socket 200 is custom made for the residual limb of itsuser. For example, perforated plastic may be drape-molded over apositive model of the user's residual limb or three-dimensionallyprinted, and covered in perforated, air-permeable fabric to createperforated inner layer 210. A carbon fiber outer frame 220 may then bemolded over the custom-molded perforated inner layer 210, and the outerframe 220 may be affixed to the perforated inner layer 210 by standardmeans, such as stitching, adhesive, and/or the like. The perforationsand fenestrations may be strategically positioned to providebreathability to the areas of the user's residual limb which heat up themost during the use of a prosthesis.

FIGS. 8C and 8D illustrate the front of socket 200 in plan view andperspective view, respectively. As illustrated, outer frame 220comprises an anterior, symmetrical fenestration on the front of socket200. This anterior fenestration enables air from the externalenvironment to pass through perforated inner layer 210, via holes 212,to the internal environment of socket 200, and/or enables air from theinternal environment of socket 200 to pass through perforated innerlayer 210, via holes 212, to the external environment. The front ofsocket 200, illustrated in FIGS. 8C and 8D, corresponds to the anteriorof the residual limb, and therefore, the anterior fenestration providesbreathability, primarily, to the anterior of the user's residual limb.

FIGS. 8E and 8F illustrate the back of socket 200 in plan view andperspective view, respectively. As illustrated, in the first embodiment,outer frame 200 comprises two, separate posterior fenestrations on theback of socket 200. Each posterior fenestration is offset from thecenter and separated from the other posterior fenestration by a strip ofouter frame 220. Each posterior fenestration enables air from theexternal environment to pass through perforated inner layer 210, viaholes 212, to the internal environment of socket 200, and/or enables airfrom the internal environment of socket 200 to pass through perforatedinner layer 210, via holes 212, to the external environment. The back ofsocket 200 corresponds to the posterior of the residual limb, andtherefore, the left-posterior fenestration provides breathability,primarily, to the left-posterior of the user's residual limb, while theright-posterior fenestration provides breathability, primarily, to theright-posterior of the user's residual limb. Advantageously, theposterior fenestrations allow air to reach the posterior of the user'sresidual limb, which is typically the area that heats up the most duringuse of prostheses.

FIGS. 9A and 9B illustrate socket 200 in side and back plan views,respectively, according to a second embodiment. Unlike the firstembodiment, the second embodiment only has a single posteriorfenestration, which may be similar or identical to the anteriorfenestration illustrated in FIGS. 8C and 8D. The second embodiment ofsocket 200 may have an anterior fenestration that is similar oridentical to the anterior fenestration of the first embodiment of socket200, illustrated in FIGS. 8C and 8D.

2. Usage of System

FIGS. 10A-10C illustrate how liner sock 100 and socket 200 may be used,according to an embodiment. As illustrated in FIG. 10A, liner sock 100may be pulled over the residual limb. This may be performed by turningliner sock 100 inside-out (e.g., as illustrated in FIG. 1C), placing thedistal end of the user's residual limb into distal cup 144, and thenrolling liner sock 100 up onto the user's residual limb. It should beunderstood that liner sock 100 may be manufactured in a variety of sizesto fit a wide range of residual limbs. A pin screw 146 may be screwedinto countersunk hole 142 on liner sock 100, either before or afterstump sock 300 and/or socket 200 have been placed over liner sock 100.

As illustrated in FIG. 10B, stump sock 300 is pulled over liner sock100. As described elsewhere herein, stump sock 300 provides volumemanagement and may be replaced with a stump sock 300 of different ply,as needed over time, due to changes in the volume of the user's residuallimb. In some cases, stump sock 300 may not be necessary, and may beomitted, in which case socket 200 may be placed directly over liner sock100.

As illustrated in FIG. 10C, socket 200 is pulled over liner sock 100and/or stump sock 300. Socket 200 may be held to liner sock 100 and theresidual limb using a pin-suspension technique or other lanyard-stylesystem on the sides or end of liner sock 100 (e.g., the systemmanufactured by Coyote Design™ of Boise, Id.). In any case, a prosthesis(e.g., a prosthetic leg and foot) may be affixed to pin screw 146, withsocket 200 providing suspension of the prosthesis from the residuallimb. Any commercial pin-locking system may be used to affix theprosthesis to pin screw 146. While embodiments are illustrated herein asusing pin suspension, it should be understood that these embodiments maybe adapted to use other common suspension means, such as sleeve,suction, and/or elevated vacuum suspension.

Advantageously, as discussed above, liner sock 100 utilizesair-permeable textile(s), with internal strips 150, 152, and/or 153, ordots 156 of silicone gel or similar friction-interface material, toprovide a comfort, friction fit. Because the outer surface of theair-permeable textile is uncovered and a significant amount of the innersurface of the air-permeable textile is uncovered, the textile of linersock 100 admits air into the inner environment of liner sock 100 andallows sweat to evaporate from the surface of the user's residual limb.In other words, liner sock 100 improves breathability in the internalenvironment of liner sock 100.

Furthermore, as discussed above, socket 200 utilizes one or morefenestrations that expose a perforated inner layer 210 to the externalenvironment. This allows air to pass between the internal and externalenvironments of socket 200, via holes 212 in perforated inner layer 210.Therefore, socket 200 improves the breathability in the internalenvironment of socket 200.

Thus, the disclosed liner sock 100 and the disclosed socket 200, bothindividually and in combination, improve ventilation and breathabilityto the user's residual limb and provide an “air-conditioned” effect. Itshould be understood that, in the event that a stump sock 300 is usedbetween liner sock 100 and socket 200, a stump sock 300 with breathablecharacteristics should be utilized, so as to not inhibit the improvedbreathability characteristics of the liner sock 100 and/or socket 200.

The above description of the disclosed embodiments is provided to enableany person skilled in the art to make or use the invention. Variousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the general principles described herein can beapplied to other embodiments without departing from the spirit or scopeof the invention. Thus, it is to be understood that the description anddrawings presented herein represent a presently preferred embodiment ofthe invention and are therefore representative of the subject matterwhich is broadly contemplated by the present invention. It is furtherunderstood that the scope of the present invention fully encompassesother embodiments that may become obvious to those skilled in the artand that the scope of the present invention is accordingly not limited.

What is claimed is:
 1. A system for use on a residual limb, the system comprising a liner sock to be worn on the residual limb, the liner sock comprising: air-permeable textile forming a substantially cylindrical portion that is closed on a distal end and open on a proximal end and comprising an internal surface and an external surface; and a friction-interface material that covers only a portion of the internal surface of the air-permeable textile, such that, when worn on the residual limb, the friction-interface material contacts a surface of the residual limb, and an uncovered portion of the air-permeable textile which the friction-interface material does not cover allows air to pass between an external environment of the liner sock and the surface of the residual limb.
 2. The system of claim 1, wherein the air-permeable textile comprises: a first section comprising unidirectional-stretch textile; and at least one second section comprising bidirectional-stretch textile.
 3. The system of claim 2, wherein the first section is fixed to the at least one second section by at least one seam, and wherein the friction-interface material covers the seam on the internal surface of the air-permeable textile.
 4. The system of claim 2, wherein the air-permeable textile comprises two second sections comprising bidirectional-stretch textile.
 5. The system of claim 2, wherein the friction-interface material covers an entire internal surface of the first section comprising unidirectional-stretch textile, but does not cover an entire internal surface of the at least one section comprising bidirectional-stretch textile.
 6. The system of claim 2, wherein the friction-interface material comprises a plurality of longitudinal strips that extend in a longitudinal direction of the liner sock and that are spaced apart from each adjacent one of the plurality of longitudinal strips, around a circumference of the liner sock, by the uncovered portion of the air-permeable textile.
 7. The system of claim 2, wherein the friction-interface material comprises a strip that extends around a circumference of the liner sock at a proximal end of the liner sock.
 8. The system of claim 2, wherein the friction-interface material comprises a plurality of circumferential strips that extend around a circumference of the liner sock and that are spaced apart from each adjacent one of the plurality of circumferential strips, in a longitudinal direction of the liner sock, by the uncovered portion of the air-permeable textile.
 9. The system of claim 2, wherein the friction-interface material comprises a plurality of dots.
 10. The system of claim 2, wherein the friction-interface material comprises a distal cup at a distal end of the liner sock.
 11. The system of claim 2, wherein the friction-interface material comprises silicone gel.
 12. The system of claim 2, wherein the liner sock further comprises a distal cap on an external surface of the closed distal end of the liner sock.
 13. The system of claim 12, wherein the distal cap comprises a countersunk threaded hole configured to receive a screw pin.
 14. The system of claim 2, further comprising a socket to be worn, either directly or indirectly, over the liner sock, the socket comprising: a perforated inner layer; and an outer frame comprising one or more fenestrations, through which the perforated inner layer is exposed to an external environment of the socket.
 15. The system of claim 14, wherein the perforated inner layer comprises a plurality of holes having a diameter of 5 millimeters or less.
 16. The system of claim 14, wherein the outer frame comprises an anterior fenestration and at least one posterior fenestration.
 17. The system of claim 16, wherein the outer frame comprises at least two posterior fenestrations.
 18. The system of claim 14, wherein the perforated inner layer comprises fabric.
 19. The system of claim 14, wherein the outer frame comprises carbon fiber. 